Backstory: I bought a Nexus 10 on Ebay and it had a bunch of custom stuff on it that I deleted and inadvertently hard bricked the device. I've spent countless hours trying to fix this and it will not accept any new (stock) roms or anything for that instance as it will not even boot into recovery, it just pops up upon loadup to the device info screen where I can select recovery etc. It will still show when I am connected via USB (fastboot). I've read that the makeshift "jig" devices can force devices into download mode.

1. Is that true?
2. Does it work for the Nexus 10?
3. If so, do you know where I can purchase one?
4. If not, do I have any other repair options?

I have worked for over ten hours on this. I have tried toolkits, I have tried to flash via fastboot but at this point I cannot get it to download the new stock rom.